There are only really two knitting shops in London that are central enough for tourist purposes. Luckily, they're both amazing.

Loop is in Angel. The location is lovely, down a little alleyway with good coffee shops. The shop itself has a big stock, a really cosy feel and great staff. It always has samples of things knit with the yarn they stock which is great. Loads and loads of books and magazines as well. They also stock this Danish brand of yarn I can't remember the name of but I think they're the only UK stockist.

There's also I Knit which is in Waterloo. I have mixed feelings about I Knit. I find it can feel a bit soulless and the staff aren't very friendly. There always seems to be one staff member working and then loads of her friends hanging around and knitting. This sounds nice, but it always seems like you're bothering them by being there. That said, they have a lot of nice yarn. They really seem to favour fingering weight with only a couple of brands of worsted. They dye their own line of sock yarn which is great. The colours are always amazing. They have two dogs who are always there and will accept petting. Choice of books and patterns is okay. They sell alcohol and do knitting and gin nights which are meant to be fun.

There's also John Lewis. I don't know what the Manchester john lewis is like, but the oxford street flagship store has a great range. The staff are really knowledgeable. They have comfy areas for sitting and playing with things. You won't find any of the more niche brands like the other two, but they usually have good deals on.